If we are talking about a direct duel between a Necromancer and a Warlock, then the latter should develop Chaos, and the former should develop magic resistance. Since each unit in the Warlock's army, at a high level of development, is capable of inflicting additional damage, comparable to the effect of two Shock Earth spells (let's say, if your hero has already passed the 20-level period). Judge for yourself.
Клан "Вершители Асхана" - "Masters of Ashan"